My conclusions are this: it is a military service but different from UVB-76, Squeaki whell or spies. Note that they use a different message syntax from those stations. I think this is correspondence for staffs or other military groups. It is a bit like the analogy of messages for Polish military missions or civil defense, but I do not know if Russia has a civil defense service.
It is obvious that all Russian services use the same names for lettering. Sometimes there are individual differences in pronunciation or subject names characteristic of some service. Even the fact that it is not a synthesizer or a man is reading but a woman, something suggests the nature of service.
I am in constant range of the military aircraft control station from the Kaliningrad region -4830USB. Only men work, reading groups of numbers characteristic of military flights as during the Warsaw Pact. Strange that they use open text (they do not use encryption), although often on this channel is broadcast digital broadcast without coordination with audio transmission.
So far I have not found the pilots' answers, unless they do it on VHF, because once I intercepted such two-sided open text correspondence at about 128MHz ..